This invention relates to integrated semiconductor devices and systems, and more particularly to features used in an electronic digital processing system of the single-chip microprocessor or microcomputer form.
Microcomputers and microprocessors of the prior art are identified in the Background of Invention in U.S. Pat. No. 4,402,044, assigned to Texas Instruments.
It is the principal object of this invention to provide an improved microcomputer or microprocessor device which is adaptable for a wide variety of uses but yet is constructed to facilitate low-cost manufacture and to minimize testing costs.
Another object is to provide a microcomputer device that is more flexible in the variety of different uses that can be programmed into a standard chip type. In particular, it is an object to provide a microcomputer device, in which the amount of microcoding employed in instruction execution can be varied without changing any masks in the manufacturing process other than a gate mask.